Waste area Grouping 2 Phase I remedial investigation: Sediment and Cesium-137 transport modeling report

Remedial investigation report on the Melton Valley Watershed at Oak Ridge National Laboratory, Oak Ridge, Tennessee. Volume 1: Evaluation, interpretation, and data summary

“…A sediment and '37Cs transport study conducted as part of the WAG 2 RI (Clapp et al 1996) concluded that releases of '37Cs by erosion of surface soils and floodplain sediments during storms are relatively small and that the vegetative cover on these soils and sediments effectively controls the release of '37Cs from the [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Melton Valley watershed. Therefore, it appears that contaminant releases that may be occurring from I subbasins in which there are contaminated floodplain sediments or surface soils are predominantly due to mechanisms other than erosion.…”

White Oak Creek Watershed: Melton Valley Area Remedial Investigation Report, Oak Ridge National Laboratory, Oak Ridge, Tennessee: Volume 1 Main Text

“…The surface water system also transports sediments and soils with particlereactive contaminants, especially 137Cs. These particle-reactive contaminants were mostly discharged directly to the stream as a result of historical activities at ORNL (Clapp et al 1996). They have accumulated in the floodplains of WOC and the sediments of WOL.…”

“…Asediment and 13' Cs transport study conducted as part of the WAG 2 RI (Clapp et al 1996) concluded that releases of 137Cs by erosion of surface soils and floodplain sediments during storms are relatively small and that the vegetative cover on these soils and sediments effectively controls the release of '37Cs from the WOC watershed. Therefore, it appears that contaminant releases that may be occurring from subbasins in which there are contaminated floodplain sediments or surface soils are predominantly due to mechanisms other than erosion.…”

“…The Intermediate Pond is a potentially significant source of 137Cs to downstream areas including the off-site environment (Clapp et al 1996). However, very little !37Cs appears to be eroded (and hence released) from the Intermediate Pond k e a on an annual basis, suggesting that the current vegetation and channel geometry result in a relatively stable condition.…”

“…Due to its inventory of 137Cs (relatively small relative to WOL, the Intermediate Pond Area, and the WOC floodplains) it remains a potential source to the off-site environment. According to WAG 2 RI results (Clapp et al 1996), the embayment can be a passive conduit or a slight source of 137Cs (i-e., a maximum of a few 1/1OOths Ci of 137Cs were mobilized d&g one . storm).…”